AMD Athlon (Thunderbird)and Duron overclocking

Before passing right to the subject I'd like to
say some words in defense of overclocking. The topicality of this
come from the fact that nowadays more and more incompetent users
become interested in overclocking. If you are considered to be a
professional I'd recommend to omit this part.

In defence of overclocking

The performance of a computer and its functional
possibilities mainly depend on parameters of elements and on their
joint coordinated operation. It's not enough only to choose a computer
and determine what it consists of. It's necessary to tweak it optimally
reaching the maximum performance of the elements and the most possible
realization of their possibilities.

But keep in mind that even carefully tweaked and
regularly serviced computer can not meet continuously rising requirements.
Sooner or later every user will face a problem of scanty performance
for solving the problems set. After all resources of increasing
the performance at the expense of thorough optimization of soft
hardware are exhausted one should take radical measures. As a rule,
some users solve the problem of insufficient performance by purchasing
a new machine, others - by upgrading the old one. The both ways
mean considerable financial expenditure. And sometimes it concerns
not an old but excellently working machine which might have been
bought a year or two ago!

However, we should notice that beside optimization
of soft hardware and their upgrade there is another way that prolong
the life of aging devices. This way helps sometimes to reanimate
those computers which you can hardly call up-to-date. This is an
overclocking method. The idea concludes in exploitation of some
computer elements in accelerated modes. As a rule, this helps to
increase efficiency of each of them and therefore the performance
of the whole system. But sometimes it can cause decrease of reliability
and reduction of no-failure operation resource, what, however, in
many cases is acceptable.

Under the condition of non-stop development of
computer technologies and appearance of more advanced soft hardware
the life of expedient exploitation of components is decreasing.
With more modern qualitative and efficient components it becomes
unprofitable to use outmoded prototypes. And this is true even despite
the enhancement of production techniques, raise of reliability and
the life of their no-failure operation. Today the life time of processors,
video adapters and HDDs is usually no more than 2-3 year. It is
in average. But many users replace their quite well operation models
by more efficient ones even earlier. At the same time we should
notice that high reliability of computer components allows to run
them over 10 years. But more advanced, efficient sample appear,
as a rule, each 2-3 months. That's why a possible reduction of reliability
and resource (e.g. from 10 to 5 years) can often be justified since
the life time of the components is short and the whole resource
won't be used up. And possible failure and buzzes with the correct
overclocking are quite rare, and under usual conditions they do
not cause fatal consequences. Of course, you shouldn't use these
modes for servers or in systems of potentially dangerous productions
control and vital processes.

Today, the overclocking of new machines becomes
popular. Some users ask to set the accelerated mode even in the
shops, but more experienced users do it at home selecting optimal
modes while strongly controlling their subsystems of the computers
at those stages.

The performance increase for processors can reach
20-30% in overclocking mode, in more tough modes it can be 50% and
more. Besides, overclocking helps to increase the performance of
video adapter RAM and even hard discs. When overclocked the entry
level components do not lag behind more powerful and expensive components.
Sometimes, you can save several hundred dollars only with a processor.

Overclocking, however, touches the interests of
companies producing computer components. They do not want lose even
a small part of income. Besides, overclocking often helps swindles
to fabricate markings of components. Some small companies produce
some devices such as video adapters, motherboards or even computers
with already overclocked components and let the customers know about
it.

The firms-manufacturers protect their commercial
interests and bring in enhancements in order to prevent it.

In spite of such stable resistance of the companies,
overclocking turns to be more and more popular. The corresponding
motherboards, chipsets and software programs appearing in the market
further it. Today the market offers a lot of cooling devices that
simplifies setting of the corresponding modes and testing.

Not just separate enthusiasts devoted themselves
to examination of overclocking but also some top companies do it.
Sometimes, such works are carried out by approbation of manufacturers.
For example, take a collaboration of KryoTech and AMD. As a result,
the processors of AMD in extreme overclocking mode reached 1 GHz
long before the company released a processor with such regular frequency.

Such investigations allow to improve technologies,
perfect architectures, increase the performance of the components.
Besides, it allows to accumulate the statistics on failure and buzzes,
it allows creating effective soft hardware means for lifting reliability.
The ability of the components to work in overclocking mode is a
perfect advertising for the corresponding companies.

AMD Athlon (Thunderbird) and Duron CPU

The processors AMD Athlon (based on the Thunderbird
core) and Duron are shipping in the PGA cases. The motherboards
intended for these processors have a special socket - PGA-socket
called Socket A (462 pins).

The Duron has 128 KBytes L1 cache and 64 KBytes
L2 cache.

The Athlon differs form the Duron only in the size
of the L2 cache: 256 KBytes.

The CPUs work with the Alpha EV6 bus developed
by the DEC company for the Alpha and licensed by AMD for their devices.

The Alpha EV6 bus provides double-data-rate. It
increases the bandwidth and ensures the performance gain. At the
clock speed equal to 100 MHz the FSB Alpha EV6, usually called EV6,
provides data transmission at 200 MHz in contrast to the GTL+ and
AGTL+ of the Celeron, Pentium II/III from Intel the data rate and
clock speed of which have the same value.

The AMD Athlon and Duron require special motherboards
which support these processors. The boards ensures stable work when
using a power supply unit less than 235 W.

The CPUs have a considerable technological reserve,
which permits performance gain at the expense of usage of overclocking
modes, e.g. rise of processor's bus frequency. However, the FSB
EV6 frequency can be lifted not more than 10-15%. The exact value
depends on the type of the motherboard you are using.

The AMD Athlon and Duron, like the CPUs Intel Pentium
II, Pentium III (Katmai, Coppermine), have a locked multiplier which
connects an internal frequency with an external one. As there used
the Socket A which excludes change of registers as it was in case
of AMD Athlon for the Slot A the multipliers can be changed only
with the help of special soft hardware means, but they are supported
by a tight circle of motherboard types.

As a result, the accelerating of work of the processors
is implemented, as a rule, at the expense of lifting an external
frequency - the FSB EV6 frequency.

Below you can see the results of the carried out
investigations connected with an analyses of possible operation
in accelerated mode of the high-efficient processors AMD Athlon
and Duron.

It's necessary to note that the core voltage mustn't
exceed 5-10% relatively the default level. The recommendations of
AMD on the supply voltage levels of the CPUs Athlon and Duron are
shown in the table below.

Admissible supply voltage levels
of AMD CPUs

Processor

Frequency, MHz

Min supply voltage, V

Standard supply voltage, V

Max supply voltage, V

Athlon

650-850

1,6

1,7

1,8

900-1000

1,65

1,75

1,85

Duron

550-700

1,4

1,5

1,6

For more precise analyses of the temp mode and
estimation of the necessary cooling means we provided the data on
the power of the AMD Duron and AMD Athlon.

AMD Athlon power

Frequency, MHz

Usual power, W

Max power, W

650

32.4

36.1

700

34.4

38.3

750

36.3

40.4

800

38.3

42.6

850

40.2

44.8

900

44.6

49.7

950

46.7

52.0

1000

48.7

54.3

AMD Duron power

Frequency, MHz

Usual power, W

Max power, W

550

18.9

21.1

600

20.4

22.7

650

21.8

24.3

700

22.9

25.5

The corresponding processor pins set the multiplier
value and the supply voltage. Some motherboards using these pins
allow changing multiplier values. For example, the Abit KT7 and
the Soltek SL-KV75+ which were used for demonstration of overclockability
of the AMD Athlon and Duron via the change of frequency multipliers.

Cooling means

There we used a cooler TITAN TTC-D2T that ensures
an effective cooling of the processors AMD. The fan is controlled
by the hardware monitoring of the VT82C686A chip.

The processor temp is measured with the sensors
(a flexible one of the SL-KV75+, and hard one of the KT7) of the
motherboard and the hardware monitoring means.

CPU overclocking with the FSB frequncy increase

In case of usage of the Soltek SL-KV75+ the clock
speed of the processor bus is chosen with one of two DIP-switches,
marked out on the photo of the SL-KV75+, and via the BIOS Setup.
For the Abit KT7 the frequency is set in the BIOS Setup. The board
Abit KT7 showed higher scores. We managed to increase the clock
speed of the processor bus up to 115 MHz. Below you can see the
results of overclocking of the processors via lifting the FSB frequency
for the Abit KT7.

Overclocking of the Duron (Abit
KT7)

CPU frequency= FSB frequency * multiplier

CPUmark 99

FPU WinMark

600 = 100 * 6

51,4

3260

672 = 112 * 6

57,8

3660

690 = 115 * 6

59,4

3760

Overclocking of the Athlon (Abit
KT7)

CPU frequency= FSB frequency * multiplier

CPUmark 99

FPU WinMark

700 = 100 *7

64,7

3810

770 = 110 * 7

71,2

4190

784 = 112 * 7

72,5

4270

Overclocking of the CPUs via change of multiplier
values

The multiplier of the AMD Athlon (Thunderbird)
and the AMD Duron is locked but the motherboards Soltek SL-KV75+
and Abit KT7 provide a possibility to change it. It concerns only
the first versions of the processors. Some time ago AMD restricted
this feature. However, fortunately for overclockers the multiplier
can be changed with the L1 bridges which are located on the processor
surface. Connecting the burnt bridges you can therefore provide
the possibility to change the multiplier. You can do it with a soft
sharp pencil drawing the burnt L1 bridges on the processor. You
should avoid closing of the neighboring bridges. The results of
the procedure see in the following pictures (for the Duron).

The highlight of this method is that you can easily
restore the bridges with the spirit.

Below you can see the AMD Athlon (Thunderbird)
which didn't need such procedure.

After restoration of the burnt bridges on the AMD
Duron the multiplier can be changed with the motherboard means.

A choice of the multiplier value with the usage
of the Soltek SL-KV75+ is implemented with the corresponding DIP-switch
(it's marked out on the photo of the board Soltek SL-KV75+).

Let's consider some features of the board Soltek
SL-KV75+. In the manual they say that LED lighting means a possibility
of usage of the means for a change of the multiplier. But the LED
was lighting even when we used the processor with the burnt L1 bridges.
While overclocking some multiplier values couldn't be set. We managed
to get only three values for the Duron 600: 6, 6.5 and 8.

The Abit KT-7 lacks for such troubles, since the
overclocking there is implemented via the BIOS Setup. That's why
here we will consider only the results received on the board Abit
KT7.

Overclocking results and the selected modes are
shown in the tables and on the diagrams below.

Overclocking of the Duron (Abit
KT7)

CPU frequency= FSB frequency *
multiplier

CPUmark 99

FPU WinMark

600 = 100 * 6

51,4

3260

650 = 100 * 6,5

55

3550

700 = 100 *7

57,6

3810

800 = 100 * 8

63,2

4350

850 = 100 * 8,5

65,8

4640

900 = 100 * 9

68,3

4900

Overclocking of the Athlon (Abit
KT7)

CPU frequency= FSB frequency *
multiplier

CPUmark 99

FPU WinMark

700 = 100 *7

57,6

3810

800 = 100 * 8

63,2

4350

Overclocking with increase of the bus frequency
and the multiplier

We should notice that the maximum performance
levels can be achieved with the optimal clock speeds of the processor
bus with the corresponding multiplier values.

The results of overclocking of the processors on
the both boards are shown below.

Overclocking of the Duron (Soltek
SL-KV75+)

CPU frequency= FSB frequency *
multiplier

CPUmark 99

FPU WinMark

600 = 100 * 6

52,7

3260

630 = 105 * 6

55,4

3430

650 = 100 * 6,5

55,9

3530

672 = 112 * 6

59,1

3660

683 = 105 * 6,5

58,8

3720

715 = 110 * 6,5

61,6

3890

800 = 100 * 8

65

4350

840 = 105 * 8

68,4

4580

Here, the max performance can be reached with the
max multiplier and the maximum bus frequency.

Overclocking of the Duron (Abit
KT7)

CPU frequency= FSB frequency *
multiplier

CPUmark 99

FPU WinMark

600 = 100 * 6

51,4

3260

650 = 100 * 6,5

55

3550

672 = 112 * 6

57,8

3660

683 = 105 * 6,5

57,4

3720

690 = 115 * 6

59,4

3760

700 = 100 *7

57,6

3810

715 = 110 * 6,5

60,2

3890

748 = 115 * 6,5

63,2

4080

770 = 110 * 7

63,5

4190

800 = 100 * 8

63,2

4350

840 = 105 * 8

66,7

4580

850 = 100 * 8,5

65,8

4640

880 = 110 * 8

69,9

4790

893 = 105 * 8,5

69,4

4860

896 = 115 * 8

71,2

4880

900 = 100 * 9

68,3

4900

910 = 107 * 8,5

70,9

4980

With the Abit KT7 we managed to achieve much higher
results - the CPU frequency rose more than 1.5 times. The maximum
performance in integer calculations is reached in the mode 896 MHz
= 115 MHz * 8, and in calculations with floating point - at 910
MHz.

Note that for reaching high frequencies it was
impossible to do without lifting core voltage and I/O circuits.
The following table shows the modes where we increased the core
voltage.

Voltage when overclocking the
Duron (Abit KT7)

CPU frequency= FSB frequency *
multiplier

Core voltage/ I/O, V

Temperature, degrees C

600 = 100 * 6

1,5 / 3,3

37

770 = 110 * 7

1,6 / 3,4

41

850 = 100 * 8,5

1,65 / 3.4

44

880 = 110 * 8

1,7 / 3,4

47

893 = 105 * 8,5

1,7 / 3,4

48

900 = 100 * 9

1,75 / 3,4

50

910 = 107 * 8,5

1,75 / 3,4

50

Some attempts of overclocking were unsuccessful
- it couldn't pass the test POST, the OS didn't boot or the computer
buzzed while passing the test. The variants, when at least the POST
was passed are indicated in the table below. The data show that
in most cases the problem of unstable work could have been solved
by increasing the processor voltage.

Attempts of overclocking the Duron
(Abit KT7)

Attempts

Voltage, V

Post

Windows

Winbench

893 = 110 * 8,5

1,65

ok

halt - error IOS

1,675

ok

Halt

1,7

ok

Ok

ok

900 = 100 * 9

1,7

ok

Ok

halt

1,75

ok

Ok

ok

927 = 103 * 9

1,75

ok

Halt

935 = 110 * 8,5

1,75

ok

Halt

Below you can see the results of overclocking the
Athlon. Despite the fact that we managed to overclock the processor
Athlon only up to 825 MHz, a tremendous performance increase was
obtained.